1. Field of the Invention
The invention relates in general to a processing method for a pair of stereo images, and more particularly to a stereo image processing method capable of simplifying a computation process.
2. Description of the Related Art
Different images of an object perceived by both human eyes give an observer a sense of distance between the object and the observer. Similarly, a so-called pair of stereo images are a pair of two-dimensional (2D) images of an environment or a target object respectively obtained from two different positions along a line. Information of another dimension may be obtained by appropriately processing the pair of 2D images. That is, distance information of objects in the images may be obtained to generate a three-dimensional (3D) image. For example, 3D images may be utilized in monitoring equipment or an interactive television game device to identify an object position in front of a camera.
To obtain a 3D image from a pair of 2D stereo images, disparity information of the 2D stereo images is needed. For example, supposing a pair of 2D images are respectively left and right images captured by left and right cameras, the disparity of a closer object with respect to the left and right images is greater than the disparity of a farther object. Thus, generating a 3D image involves theoretically identifying the disparity of each pixel of one of two 2D images, or generating a disparity map formed by a plurality of disparities corresponding to the pixels.
However, in the prior art, complicated computations and large amounts memory or number of registers are required for generating a disparity map. For example, a conventional method for determining a disparity of a pixel in a left image is first defining a predetermined range around the pixel as a source image window. Next, from a right image, among a plurality of destination image windows corresponding to all the disparities of the pixel, a destination image window most similar to the source image window is identified. The disparity between the most similar destination image window and the source image window is the disparity corresponding to the pixel. Computations involved in such a conventional approach are significant. Although certain improved methods have been proposed, e.g., a method disclosed by U.S. Pat. No. 7,876,954, computations required for realizing the improved methods are still quite sizable.